This invention relates to a novel nitrogen-containing carbohydrate having activity against transplanted Krebs-2 and Sarcoma-180 tumors in mice.
It has been experimentally observed that a proliferating tissue, e.g. embryonal liver tissue, inhibits growth of tumor when they are injected in an experimental tumor-bearing animal, and the phenomenon has been discussed in relation to common antigenicity on the cell membranes of embryonal liver cells and tumor cells. That is to say, it has been recognized that common anti-bodies are produced in a body of the tumor-bearing animal in a higher concentration than usual by the injection of embryonal liver cells and, as a result, growth of tumor is inhibited immunologically, since tumor cells and embryonal liver cells are similar to each other in the point of their high proliferation speed and these two kinds of cells have several kinds of common antigens on their cell membranes. Thus, it is known that a proliferating tissue has anti-tumoral activity, but it has been thought that its anti-tumoral activity is due to its immunological mechanism and has not been thought that it is due to direct effect of a special substance in the proliferating tissue.
The present inventor found that proliferating tissues, e.g. tumor tissue, embryonal tissue and germ tissue, have a characteristic nitrogen-containing carbohydrate commonly on their cell membranes and has completed this invention through further investigation of cell fractions of these tissues.